U.S. patent application number 17/470749 was filed with the patent office on 2021-12-30 for developing cartridge including coupling and clutch for allowing rotation of coupling in first direction and stopping rotation of coupling in second direction.
This patent application is currently assigned to BROTHER KOGYO KABUSHIKI KAISHA. The applicant listed for this patent is BROTHER KOGYO KABUSHIKI KAISHA. Invention is credited to Keita SHIMIZU.
Application Number | 20210405551 17/470749 |
Document ID | / |
Family ID | 1000005828166 |
Filed Date | 2021-12-30 |
United States Patent
Application |
20210405551 |
Kind Code |
A1 |
SHIMIZU; Keita |
December 30, 2021 |
DEVELOPING CARTRIDGE INCLUDING COUPLING AND CLUTCH FOR ALLOWING
ROTATION OF COUPLING IN FIRST DIRECTION AND STOPPING ROTATION OF
COUPLING IN SECOND DIRECTION
Abstract
A developing cartridge includes: a developing roller; a coupling
for rotating the developing roller; a shaft; and a clutch. The
developing roller is rotatable about a first axis extending in an
axial direction. The coupling is rotatable about a second axis
extending in the axial direction. The shaft rotatably supports the
coupling. The clutch is rotatable together with the coupling about
the shaft in a case where the coupling rotates in a first
rotational direction. In a case where the coupling rotates in a
second rotational direction opposite to the first rotational
direction, the clutch engages with a portion of the shaft and the
clutch and the coupling do not rotate.
Inventors: |
SHIMIZU; Keita;
(Nagoya-shi,, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BROTHER KOGYO KABUSHIKI KAISHA |
Nagoya-shi |
|
JP |
|
|
Assignee: |
BROTHER KOGYO KABUSHIKI
KAISHA
Nagoya-shi
JP
|
Family ID: |
1000005828166 |
Appl. No.: |
17/470749 |
Filed: |
September 9, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16578858 |
Sep 23, 2019 |
11126109 |
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17470749 |
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PCT/JP2018/011008 |
Mar 20, 2018 |
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16578858 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03G 21/1864 20130101;
G03G 15/0121 20130101; G03G 15/757 20130101; G03G 21/1676 20130101;
G03G 15/0808 20130101; G03G 21/1857 20130101; G03G 21/1647
20130101; G03G 21/186 20130101 |
International
Class: |
G03G 15/08 20060101
G03G015/08; G03G 15/01 20060101 G03G015/01; G03G 15/00 20060101
G03G015/00; G03G 21/18 20060101 G03G021/18; G03G 21/16 20060101
G03G021/16 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2017 |
JP |
2017-089273 |
Claims
1. A cartridge comprising: a roller; a coupling for rotating the
roller; a shaft rotatably supporting the coupling; and a clutch
rotatable together with the coupling in a case where the coupling
rotates in a first rotational direction, wherein, in a case where
the coupling rotates in a second rotational direction opposite to
the first rotational direction, the clutch engages with a portion
of the shaft and the clutch and the coupling do not rotate.
2. The cartridge according to claim 1, wherein the clutch is
movable between: a first position where the clutch engages with the
portion of the shaft; and a second position where the clutch is
disengaged from the portion of the shaft.
3. The cartridge according to claim 1, wherein the clutch is
movable between: a first position where the clutch engages with the
portion of the shaft; and a second position where the clutch is
spaced away from the portion of the shaft.
4. The cartridge according to claim 3, wherein the clutch is
movable relative to the shaft.
5. The cartridge according to claim 3, wherein the clutch is
movable relative to the coupling.
6. The cartridge according to claim 3, wherein the coupling is
immovable relative to the shaft.
7. The cartridge according to claim 3, wherein the shaft has a
hollow cylindrical shape, and wherein the clutch is rotatably
supported by an inner circumferential surface of the shaft.
8. The cartridge according to claim 3, wherein the shaft has a
first shaft surface and a second shaft surface, wherein, in a case
where the clutch rotates in the second rotational direction, the
first shaft surface faces the clutch in the second rotational
direction and contacts the clutch, and wherein, in a case where the
clutch rotates in the first rotational direction, the second shaft
surface moves the clutch toward the second position.
9. The cartridge according to claim 8, wherein, in a case where the
clutch contacts the first shaft surface, the first shaft surface
stops rotation of the clutch in the second rotational
direction.
10. The cartridge according to claim 8, wherein the shaft comprises
a first protrusion having the first shaft surface and the second
shaft surface.
11. The cartridge according to claim 10, wherein the shaft
comprises a plurality of the first protrusions, and wherein the
plurality of the first protrusions are arranged in a rotational
direction of the coupling.
12. The cartridge according to claim 8, wherein the clutch has: a
first clutch surface configured to contact the first shaft surface;
and a second clutch surface configured to contact the second shaft
surface.
13. The cartridge according to claim 12, wherein the clutch
comprises a second protrusion having the first clutch surface and
the second clutch surface.
14. The cartridge according to claim 13, wherein the clutch
comprises a plurality of the second protrusions, and wherein the
plurality of the second protrusions are arranged in a rotational
direction of the coupling.
15. The cartridge according to claim 11, wherein the clutch
comprises a plurality of second protrusions, each of the plurality
of second protrusions having: a first clutch surface configured to
contact the first shaft surface; and a second clutch surface
configured to contact the second shaft surface, wherein, in a case
where the coupling rotates in the first rotational direction, each
of the second clutch surfaces of the second protrusions contacts a
corresponding one of the second shaft surfaces of the first
protrusions, so that the clutch moves to the second position and
rotates together with the coupling, and wherein, in a case where
the coupling rotates in the second rotational direction, each of
the first clutch surfaces of the second protrusions contacts a
corresponding one of the first shaft surfaces of the first
protrusions, so that the rotation of the coupling in the second
rotational direction stops together with the clutch.
16. The cartridge according to claim 8, wherein the coupling has a
first coupling surface, and wherein, in a case where the clutch
rotates in the first rotational direction, the first coupling
surface moves the clutch toward the second position.
17. The cartridge according to claim 16, wherein the clutch has a
third clutch surface configured to contact the first coupling
surface.
18. The cartridge according to claim 1, wherein the coupling
comprises a recessed portion configured to receive driving
force.
19. The cartridge according to claim 1, further comprises a casing
configured to accommodate therein developing agent.
20. The cartridge according to claim 1, wherein the roller is a
developing roller.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 16/578,858, filed Sep. 23, 2019, which is a by-pass
continuation of International Application No. PCT/JP2018/011008
filed Mar. 20, 2018 claiming a priority from Japanese Patent
Application No. 2017-089273 filed Apr. 28, 2017. The entire
contents of the priority applications and the international
application are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a developing cartridge
including a coupling to which driving force is inputted.
BACKGROUND
[0003] Conventionally, there is known a developing cartridge
including a developing roller and a coupling.
SUMMARY
[0004] For example, when the developing cartridge is attached to an
image forming apparatus, the coupling receives driving force from
the image forming apparatus and rotates in a first rotational
direction. Then, the developing roller rotates in accordance with
the rotation of the coupling in the first rotational direction. By
this, the image forming apparatus can perform image formation. In
this case, if the coupling rotates in a second rotational direction
opposite to the first rotational direction, the developing roller
may rotate in a reverse direction which is opposite to the
rotational direction for the image formation and thus leakage of
developing agent may occur.
[0005] In view of the foregoing, it is an object of the present
disclosure to provide a developing cartridge capable of suppressing
the coupling from rotating in the second rotational direction which
is opposite to the first rotational direction.
[0006] In order to attain the above object and other objects, the
present disclosure provides a developing cartridge including: a
developing roller; a coupling for rotating the developing roller; a
shaft; and a clutch. The developing roller is rotatable about a
first axis extending in an axial direction. The coupling is
rotatable about a second axis extending in the axial direction. The
shaft rotatably supports the coupling. The clutch is rotatable
together with the coupling about the shaft in a case where the
coupling rotates in a first rotational direction. In a case where
the coupling rotates in a second rotational direction opposite to
the first rotational direction, the clutch engages with a portion
of the shaft and the clutch and the coupling do not rotate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The particular features and advantages of the embodiment(s)
as well as other objects will become apparent from the following
description taken in connection with the accompanying drawings, in
which:
[0008] FIG. 1 is a schematic view illustrating a structure of a
printer including a developing cartridge according to one
embodiment of the present disclosure;
[0009] FIG. 2 is a cross-sectional view illustrating a structure of
a casing of the developing cartridge;
[0010] FIG. 3 is a perspective view illustrating one side portion
of the developing cartridge in a first direction;
[0011] FIG. 4 is an exploded perspective view illustrating
components positioned at one side portion of the casing in the
first direction;
[0012] FIG. 5 is a perspective view illustrating the other side
portion of the developing cartridge in the first direction;
[0013] FIG. 6 is a perspective view of a first bearing member as
viewed from one side in the first direction;
[0014] FIG. 7(a) is a perspective view illustrating a clutch as
viewed from the one side in the first direction;
[0015] FIG. 7(b) is a perspective view illustrating the clutch as
viewed from the other side in the first direction.
[0016] FIG. 8 (a) is a perspective view illustrating a coupling as
viewed from the one side in the first direction;
[0017] FIG. 8 (b) is a perspective view illustrating the coupling
as viewed from the other side in the first direction;
[0018] FIG. 8(c) is a plan view illustrating the coupling as viewed
from the other side in the first direction;
[0019] FIG. 8(d) is a cross-sectional view of a first protruding
piece of the coupling taken along a plane X-X extending in a
rotational direction;
[0020] FIG. 9(a) is a view illustrating positional relationship
among portions of the coupling, the clutch, and a shaft when the
clutch is positioned at a first position;
[0021] FIG. 9(b) is a view illustrating the positional relationship
among the portions of the coupling, the clutch, and a shaft when
the clutch is positioned at the first position;
[0022] FIG. 10(a) is a view illustrating the positional
relationship among the portions of the coupling, the clutch, and
the shaft when the clutch is positioned at a second position;
and
[0023] FIG. 10(b) is a view illustrating the positional
relationship among the portions of the coupling, the clutch, and
the shaft when the clutch is positioned at the second position.
DETAILED DESCRIPTION
[0024] An embodiment of the present disclosure will be described
while referring to the accompanying drawings.
[0025] As illustrated in FIG. 1, a laser printer 1 mainly includes
a main body casing 2, a sheet-feeding unit 3, an image-forming unit
4, and a control device CU.
[0026] The main body casing 2 includes a front cover 2A and a
discharge tray 2B positioned at an upper portion of the main body
casing 2. The main body casing 2 has therein the sheet-feeding unit
3 and the image-forming unit 4. By opening the front cover 2A, a
developing cartridge 10 can be detached from and attached to the
main body casing 2.
[0027] The sheet-feeding unit 3 accommodates sheets S. The
sheet-feeding unit 3 feeds the sheets S one by one to the
image-forming unit 4.
[0028] The image-forming unit 4 includes a process cartridge 4A, an
exposure unit (not illustrated), a transfer roller 4B, and a fixing
device 4C.
[0029] The process cartridge 4A includes a drum cartridge 5 and the
developing cartridge 10. The developing cartridge 10 can be
attached to and detached from the drum cartridge 5. In a state
where the developing cartridge 10 is attached to the drum cartridge
5, the developing cartridge 10 is attached to and detached from the
laser printer 1 as the process cartridge 4A. The drum cartridge 5
includes a frame 5A and a photosensitive drum 5B rotatably
supported by the frame 5A.
[0030] As illustrated in FIG. 2, the developing cartridge 10
includes a casing 11, a developing roller 12, a supply roller 13,
and an agitator 14.
[0031] The casing 11 includes a container 11A and a cover 11B. The
container 11A of the casing 11 can accommodate therein toner T. The
toner T is an example of developing agent.
[0032] The developing roller 12 includes: a developing-roller shaft
12A extending in a first direction; and a roller portion 12B. Here,
the first direction is an axial direction of the developing roller
12 and hereinafter sometimes referred to simply as "axial
direction". The roller portion 12B covers an outer circumferential
surface of the developing-roller shaft 12A. The roller portion 12B
is made of an electrically conductive rubber or the like. The
developing roller 12 is rotatable about the developing-roller shaft
12A. In other words, the developing roller 12 is rotatable about a
first axis 12X extending in the axial direction. The developing
roller 12 is supported by the casing 11 so as to be rotatable about
the developing-roller shaft 12A. That is, the roller portion 12B is
rotatable together with the developing-roller shaft 12A. Developing
bias is applied to the developing roller 12 from the control device
CU.
[0033] The container 11A and the cover 11B of the casing 11 face
each other in a second direction. The second direction crosses the
first direction. Preferably, the second direction is orthogonal to
the first direction. The developing roller 12 is positioned at one
end portion of the casing 11 in a third direction. The third
direction crosses both the first direction and the second
direction. Preferably, the third direction is orthogonal to both
the first direction and the second direction.
[0034] The supply roller 13 includes: a supply-roller shaft 13A
extending in the first direction; and a roller portion 13B. The
roller portion 13B covers an outer circumferential surface of the
supply-roller shaft 13A. The roller portion 13B is made of sponge
or the like. The supply roller 13 is rotatable about the
supply-roller shaft 13A. In other words, the supply roller 13 is
rotatable about a third axis 13X extending in the axial direction.
The roller portion 13B is rotatable together with the supply-roller
shaft 13A.
[0035] The agitator 14 includes an agitator shaft 14A and a
flexible sheet 14B. The agitator shaft 14A is rotatable about a
fourth axis 14X extending in the first direction. The agitator
shaft 14A is supported by the casing 11 so as to be rotatable about
the fourth axis 14X. The agitator 14 is rotatable together with a
coupling 22 described later. A base end of the flexible sheet 14B
is fixed to the agitator shaft 14A, and a free end of the flexible
sheet 14B is configured to contact an inner surface of the casing
11. The agitator 14 can agitate toner T by rotation of the flexible
sheet 14B.
[0036] The drum cartridge 5 further includes a pressure member 5C
and an urging member 5D. The pressure member 5C is configured to
press the developing roller 12 against the photosensitive drum 5B.
The urging member 5D is configured to urge the pressure member 5C
toward the photosensitive drum 5B.
[0037] As illustrated in FIG. 1, the transfer roller 4B faces the
photosensitive drum 5B. The transfer roller 4B conveys the sheet S
while nipping the sheet S between the transfer roller 4B and the
photosensitive drum 5B.
[0038] The photosensitive drum 5B is charged by a charger (not
illustrated) and is exposed to light by the exposure unit (not
illustrated), so that an electrostatic latent image is formed on
the photosensitive drum 5B. The developing cartridge 10 supplies
toner T to the latent image to form a toner image on the
photosensitive drum 5B. In a process in which the sheet S that has
been fed from the sheet-feeding unit 3 passes between the
photosensitive drum 5B and the transfer roller 4B, the toner image
on the photosensitive drum 5B is transferred onto the sheet S.
[0039] The fixing device 4C is configured to thermally fix the
toner image transferred onto the sheet S to the sheet S. The sheet
S to which the toner image has been thermally fixed is discharged
onto the discharge tray 2B outside the main body casing 2.
[0040] The control device CU is a device configured to control the
overall operations of the laser printer 1.
[0041] The laser printer 1 further includes a sensor 7. The sensor
7 is a sensor for detecting whether or not the developing cartridge
10 is a new developing cartridge or identifying the specification
of the developing cartridge 10. The sensor 7 includes: a lever 7A
pivotably supported by the main body casing 2; and an optical
sensor 7B. The lever 7A is positioned at a position where the lever
7A can contact a protrusion and the like that are rotatable
together with a detection gear 200 described later. The optical
sensor 7B is connected to the control device CU and outputs
detection signals to the control device CU. The control device CU
is configured to determine the specification and the like of the
developing cartridge 10 on a basis of the signals received from the
optical sensor 7B. The optical sensor 7B detects displacement of
the lever 7A and transmits the detection signals to the control
device CU. More specifically, for example, a sensor unit that
includes a light-emitting portion and a light-receiving portion is
employed as the optical sensor 7B.
[0042] Next, the structure of the developing cartridge 10 will be
described in detail. As illustrated in FIGS. 3 and 4, the
developing cartridge 10 includes, at one side portion of the casing
11 in the first direction, a first gear cover 21, the coupling 22,
a developing gear 23, a supply gear 24, a first agitator gear 25,
an idle gear 26, a first bearing member 27 as an example of a
bearing member, a clutch 40, and a cap 28.
[0043] The first gear cover 21 supports the idle gear 26 by a shaft
(not illustrated) and covers at least one of the gears positioned
at the one side portion of the casing 11. The first gear cover 21
is fixed to an outer surface 11C by screws 29. The outer surface
11C is an outer surface positioned on the one side portion of the
casing 11 in the first direction.
Note that, the term "gear" in the present specification is not
limited to a member that includes gear teeth and transmits
rotational force through the gear teeth, but also includes a member
that transmits rotational force through friction. In the latter
case, rubber and the like are used instead of gear teeth. In a case
where the member that transmits rotational force through friction
is employed, a circle passing along the friction-transmitting
surface (a surface of the rubber is the friction-transmitting
surface in a case where rubber is used instead of gear teeth) is
defined as an addendum circle.
[0044] The coupling 22 is a member for rotating the developing
roller 12 and the like. The coupling 22 is rotatable about a second
axis 22X extending in the axial direction. The coupling 22 is
positioned at the one side portion of the casing 11 in the first
direction. That is, the coupling 22 is positioned at the outer
surface 11C. The coupling 22 can rotate in a first rotational
direction D1 by receiving driving force. Specifically, the coupling
22 can receive driving force from the laser printer 1. The coupling
22 can rotate by engaging with a drive member (not illustrated)
provided in the laser printer 1. The coupling 22 includes a first
recessed portion 22A at one end of the coupling 22 in the axial
direction. The first recessed portion 22A is recessed in the first
direction. The first recessed portion 22A can receive and engage
with the drive member. More specifically, the first recessed
portion 22A can engage with the drive member of the laser printer 1
and receive the driving force from the drive member.
[0045] The coupling 22 includes: a first gear 22B in meshing
engagement with the developing gear 23; and a second gear 22C in
meshing engagement with the supply gear 24. A diameter of the first
gear 22B is different from a diameter of the second gear 22C.
Specifically, the diameter of the first gear 22B is greater than
the diameter of the second gear 22C.
[0046] The developing gear 23 is attached to the developing-roller
shaft 12A. The developing gear 23 is rotatable together with the
developing roller 12 about the first axis 12X. The developing gear
23 is positioned at the one side portion of the casing 11 in the
first direction. That is, the developing gear 23 is positioned at
the outer surface 11C.
[0047] The supply gear 24 is attached to the supply-roller shaft
13A. The supply gear 24 is rotatable together with the supply
roller 13 about the third axis 13X. The supply gear 24 is
positioned at the one side portion of the casing 11 in the first
direction. That is, the supply gear 24 is positioned at the outer
surface 11C.
[0048] The first agitator gear 25 is positioned at the one side
portion of the casing 11 in the first direction. That is, the first
agitator gear 25 is positioned at the outer surface 11C. The first
agitator gear 25 is attached to the agitator shaft 14A of the
agitator 14. The first agitator gear 25 is rotatable together with
the agitator 14 in accordance with rotation of the coupling 22.
[0049] The idle gear 26 is positioned at the one side portion of
the casing 11 in the first direction. That is, the idle gear 26 is
positioned at the outer surface 11C. The idle gear 26 includes: a
large-diameter portion 26A in meshing engagement with the first
gear 22B of the coupling 22; and a small-diameter portion 26B in
meshing engagement with the gear teeth of the first agitator gear
25. The idle gear 26 is rotatably supported by the shaft (not
illustrated) of the first gear cover 21. The idle gear 26
decelerates rotation of the coupling 22 and transmits the
decelerated rotation to the first agitator gear 25. The
large-diameter portion 26A is positioned farther from the casing 11
in the first direction than the small-diameter portion 26B is from
the casing 11 in the first direction.
[0050] The cap 28 covers one end of the developing-roller shaft 12A
which is at the one side in the first direction. Note that the
first gear cover 21 and the cap 28 may be made of different kinds
of resin.
[0051] The first bearing member 27 rotatably supports the coupling
22, the clutch 40, the developing gear 23, and the supply gear 24.
The first bearing member 27 is fixed to the one side portion of the
casing 11 in the first direction. The first bearing member 27
includes a base portion 27A, a shaft 27B, and a developing agent
receiving portion 27C. The shaft 27B protrudes from the base
portion 27A toward the one side in the first direction. The
developing agent receiving portion 27C protrudes toward the other
side in the first direction from one end portion of the base
portion 27A which is at one side in the third direction.
[0052] The base portion 27A has a first hole H1 and a second hole
H2. The developing roller shaft 12A which is a rotation shaft of
the developing roller 12 is inserted through the first hole H1. The
supply-roller shaft 13A is inserted through the second hole H2. The
first hole H1 is an example of a hole.
[0053] The shaft 27B has a hollow cylindrical shape. The shaft 27B
rotatably supports the coupling 22 and the clutch 40. Specifically,
an outer circumferential surface B11 (see FIG. 6) of the shaft 27B
rotatably supports the coupling 22. An inner circumferential
surface B12 (see FIG. 6) of the shaft 27B rotatably supports the
clutch 40. More specifically, the shaft 27B has a hole B13 (see
FIG. 6). The hole B13 is a recess recessed in the axial direction
or a through-hole extending in the axial direction. The clutch 40
is positioned in the hole B13. Accordingly, the clutch 40 rotates
along the inner circumferential surface B12 of the hole B13. That
is, the clutch 40 is rotatable together with the coupling 22
relative to the shaft 27B.
[0054] The clutch 40 has a function of allowing rotation of the
coupling 22 in the first rotational direction D1 (clockwise
direction in FIG. 6). Further, the clutch 40 has a function of
stopping rotation of the coupling 22 in a second rotational
direction D2 opposite to the first rotational direction D1.
Specifically, as illustrated in FIGS. 9 to 10, the clutch 40 is
rotatable together with the coupling 22 and is movable relative to
the shaft 27B in the axial direction. The clutch 40 is movable
between: a first position where the clutch 40 engages with a
portion (first protrusions P1 described later) of the shaft 27B in
the rotational direction; and a second position where the clutch 40
is disengaged from the portion of the shaft 27B. In other words,
the clutch 40 is movable between: the first position where the
clutch 40 engages with the portion of the shaft 27B; and the second
position where the clutch 40 is spaced away from the portion of the
shaft 27B in the axial direction.
[0055] In a case where the coupling 22 rotates in the first
rotational direction D1, the clutch 40 is positioned at the second
position and thus the coupling 22 rotates together with the clutch
40. On the other hand, in a case where the coupling 22 rotates in
the second rotational direction D2, the clutch 40 moves to the
first position and thus engages with the portion of the shaft 27B.
By this, the rotation of the clutch 40 is stopped by the portion of
the shaft 27B, so that the coupling 22 rotating together with the
clutch 40 does not rotate in the second rotational direction D2 any
further.
[0056] Note that the coupling 22 does not move relative to the
shaft 27B in a direction away from the outer surface 11C of the
casing 11 since the coupling 22 contacts the first gear cover 21.
Here, "the coupling 22 does not move relative to the shaft 27B"
denotes not only that the coupling is completely immovable but also
that the coupling 22 slightly moves due to looseness. The clutch 40
is movable relative to the coupling 22 in the axial direction.
[0057] As illustrated in FIG. 5, the developing agent receiving
portion 27C is positioned at an end portion of the developing
roller 12 in the axial direction. Specifically, the developing
agent receiving portion 27C is positioned at an end portion in the
axial direction of the roller portion 12B of the developing roller
12. The developing agent receiving portion 27C has a V-shaped
cross-section taken along a plane orthogonal to the axial
direction.
[0058] The developing cartridge 10 includes, at the other side
portion of the casing 11 in the first direction, a second gear
cover 31, a second agitator gear 100, the detection gear 200, a
second bearing member 34, a developing electrode 35, and a supply
electrode 36.
[0059] The second gear cover 31 is a cover covering at least a
portion of the detection gear 200. The second gear cover 31 is
positioned at an outer surface of the container 11A of the casing
11, the outer surface being at the other side in the first
direction. The second gear cover 31 has an opening 31A. By the
opening 31A, a portion of the detection gear 200 is exposed.
[0060] The second agitator gear 100 is positioned at the other side
portion of the casing 11 in the first direction. That is, the
second agitator gear 100 is positioned at the outer surface of the
container 11A of the casing 11, the outer surface being at the
other side in the first direction. The second agitator gear 100 is
attached to the agitator shaft 14A (see FIG. 2). Accordingly, the
second agitator gear 100 is rotatable together with the agitator
shaft 14A of the agitator 14 about the fourth axis 14X extending in
the axial direction.
[0061] The detection gear 200 is positioned at the other side
portion of the casing 11 in the first direction. The detection gear
200 is rotatable together with the second agitator gear 100 when
the detection gear 200 engages with the second agitator gear
100.
[0062] The detection gear 200 includes a plurality of detection
protrusions 261 which can contact the lever 7A (see FIG. 1) of the
sensor 7. Note that, by changing the number of the detection
protrusions 261 and the positions of the detection protrusions 261
in accordance with the specification of the developing cartridge
10, the developing cartridges 10 of various specifications can be
identified by the control device CU.
[0063] The second bearing member 34 rotatably supports the
developing-roller shaft 12A and the supply-roller shaft 13A. In a
state where the second bearing member 34 supports the
developing-roller shaft 12A and the supply-roller shaft 13A, the
second bearing member 34 is fixed to the outer surface of the
container 11A of the casing 11, the outer surface being at the
other side in the first direction.
[0064] The developing electrode 35 is positioned at the other side
portion of the casing 11 in the first direction. The developing
electrode 35 supplies electric power to the developing-roller shaft
12A. The developing electrode 35 is made of electrically conductive
resin, for example.
[0065] The supply electrode 36 is positioned at the other side
portion of the casing 11 in the first direction. The supply
electrode 36 supplies electric power to the supply-roller shaft
13A. The supply electrode 36 is made of electrically conductive
resin, for example.
[0066] Together with the second bearing member 34, the developing
electrode 35 and the supply electrode 36 are fixed by screws 38 to
an outer surface positioned at the other side portion of the casing
11 in the first direction.
[0067] As illustrated in FIG. 6, the shaft 27B includes a hollow
cylindrical wall B1, a bottom wall portion B2, and the plurality of
first protrusions P1. The hollow cylindrical wall B1 has a hollow
cylindrical shape. The hollow cylindrical wall B1 has the outer
circumferential surface B11 and the inner circumferential surface
B12. The bottom wall portion B2 is positioned at one end portion of
the hollow cylindrical wall B1 in the axial direction. The bottom
wall portion B2 has a disc-like shape. The bottom wall portion B2
has a hole B3. The hole B3 penetrates the center portion of the
bottom wall portion B2 in the first direction.
[0068] The plurality of first protrusions P1 protrude from the
bottom wall portion B2 toward the other end portion in the axial
direction of the hollow cylindrical wall B1. The plurality of first
protrusions P1 are arranged in the rotational direction of the
coupling 22. The plurality of first protrusions P1 are arranged in
an annular fashion. The plurality of first protrusions P1 are
positioned in the hole B13 defined by the hollow cylindrical wall
B1. The plurality of first protrusions P1 are positioned at the one
end portion of the hollow cylindrical wall B1 in the axial
direction. Each of the first protrusions P1 has: a first shaft
surface FS1 along the first direction; and a second shaft surface
FS2 inclined relative to the first direction.
[0069] The first shaft surface FS1 is a surface for stopping
rotation of the clutch 40 in the second rotational direction D2.
The first shaft surface FS1 crosses the rotational direction of the
clutch 40. Preferably, the first shaft surface FS1 is orthogonal to
the rotational direction of the clutch 40. In a case where the
clutch 40 rotates in the second rotational direction D2, the first
shaft surface FS1 faces and contacts the clutch 40 (specifically, a
first clutch surface FC1 described later; see FIG. 7) in the second
rotational direction D2.
[0070] The second shaft surface FS2 is a surface for moving the
clutch 40 from the first position toward the second position in a
case where the clutch 40 rotates in the first rotational direction
D1. The second shaft surface FS2 is inclined relative to the
rotational direction of the clutch 40. Specifically, the second
shaft surface FS2 is inclined so as to approach the other end
portion in the axial direction of the hollow cylindrical wall B1 as
it goes in the first rotational direction D1.
[0071] As illustrated in FIGS. 7(a) and 7(b), the clutch 40
includes: a base portion 41 having a disc-like shape; a plurality
of second protrusions P2; a shaft portion 42; a first wall 43; a
first arc wall 44; a second wall 45; and a second arc wall 46. The
plurality of second protrusions P2 protrude from one surface of the
base portion 41, the one surface being at one side in the axial
direction of the clutch 40. The shaft portion 42, the first wall
43, the first arc wall 44, the second wall 45, and the second arc
wall 46 protrude from the other surface of the base portion 41, the
other surface being at the other side in the axial direction of the
clutch 40.
[0072] The plurality of second protrusions P2 are arranged in the
rotational direction of the coupling 22. The plurality of second
protrusions P2 are arranged in an annular fashion. Each of the
second protrusions P2 has a first clutch surface FC1 and a second
clutch surface FC2. The first clutch surface FC1 is along the first
direction. The second clutch surface FC2 is inclined relative to
the first direction.
[0073] The first clutch surface FC1 is a surface for stopping
rotation of the clutch 40 in the second rotational direction D2.
The first clutch surface FC1 crosses the rotational direction of
the clutch 40. Preferably, the first clutch surface FC1 is
orthogonal to the rotational direction of the clutch 40. The first
clutch surface FC1 is configured to contact the first shaft surface
FS1 (see FIG. 6). Specifically, the first clutch surface FC1 is
configured to surface-contact the first shaft surface FS1.
[0074] The second clutch surface FC2 is a surface for moving the
clutch 40 from the first position toward the second position in a
case where the clutch 40 rotates in the first rotational direction
D1. The second clutch surface FC2 is inclined relative to the
rotational direction of the clutch 40. Specifically, the second
clutch surface FC2 is inclined so as to approach the base portion
41 as it goes in the first rotational direction D1. The second
clutch surface FC2 is configured to contact the second shaft
surface FS2 (see FIG. 6). Specifically, the second clutch surface
FC2 is configured to surface-contact the second shaft surface
FS2.
[0075] The shaft portion 42 extends from the center portion of the
base portion 41 toward the other side in the axial direction of the
clutch 40. The shaft portion 42 has a hollow cylindrical shape.
[0076] The first wall 43 extends radially outwardly from the shaft
portion 42. The first wall 43 has a first surface 43A and a second
surface 43B. The first surface 43A and the second surface 43B are
orthogonal to the rotational direction. The first surface 43A is
directed downstream in the second rotational direction D2. The
second surface 43B is directed upstream in the second rotational
direction D2. The first surface 43A has a third protrusion 47. The
third protrusion 47 protrudes from the first surface 43A. The third
protrusion 47 extends along an outer circumferential surface of the
shaft portion 42. The third protrusion 47 has a third clutch
surface FC3.
[0077] The third clutch surface FC3 is a surface for moving the
clutch 40 from the first position toward the second position in a
case where the coupling 22 rotates in the first rotational
direction D1. The third clutch surface FC3 is inclined relative to
the rotational direction of the clutch 40. Specifically, the third
clutch surface FC3 is inclined so as to approach the base portion
41 as it goes in the first rotational direction D1. In a case where
the coupling 22 rotates in the first rotational direction D1, the
third clutch surface FC3 contacts a coupling surface FP1 described
later (see FIG. 10(b)).
[0078] The first arc wall 44 extends in the second rotational
direction D2 from a radially outer end portion of the first wall
43. The first arc wall 44 has an arc shape whose center is the
second axis 22X. An outer circumferential surface of the first arc
wall 44 and an outer circumferential surface of the base portion 41
are flush with each other. The outer circumferential surface of the
first arc wall 44 and the outer circumferential surface of the base
portion 41 are rotatably supported by the inner circumferential
surface B12 (see FIG. 6) of the shaft 27B. Specifically, the outer
circumferential surface of the first arc wall 44 and the outer
circumferential surface of the base portion 41 are cylindrical
surfaces whose center is the second axis 22X. Also, the inner
circumferential surface B12 is a cylindrical surface whose center
is the second axis 22X. The outer circumferential surface of the
first arc wall 44 and the outer circumferential surface of the base
portion 41 are in surface-contact with the inner circumferential
surface B12 of the shaft 27B. Accordingly, the clutch 40 moves in a
direction along the second axis 22X while rotating about the second
axis 22X.
[0079] The second wall 45 is positioned at the opposite side to the
first wall 43 relative to the second axis 22X. The second wall 45
extends radially outwardly from the shaft portion 42. The second
wall 45 has a third surface 45A and a fourth surface 45B. The third
surface 45A and the fourth surface 45B are orthogonal to the
rotational direction. The third surface 45A is directed downstream
in the second rotational direction D2. The fourth surface 45B is
directed upstream in the second rotational direction D2. The third
surface 45A has a fourth protrusion 48. The fourth protrusion 48
protrudes from the third surface 45A. The fourth protrusion 48
extends along the outer circumferential surface of the shaft
portion 42. The fourth protrusion 48 has a fourth clutch surface
FC4.
[0080] The fourth clutch surface FC4 is a surface for moving the
clutch 40 from the first position toward the second position in a
case where the coupling 22 rotates in the first rotational
direction D1. The fourth clutch surface FC4 is inclined relative to
the rotational direction of the clutch 40. Specifically, the fourth
clutch surface FC4 is inclined so as to approach the base portion
41 as it goes in the first rotational direction D1. In a case where
the coupling 22 rotates in the first rotational direction D1, the
fourth clutch surface FC4 contacts a second coupling surface FP2
described later (see FIGS. 8(c) and 8(d)). The fourth clutch
surface FC4 is positioned at the opposite side to the third clutch
surface FC3 relative to the second axis 22X.
[0081] The second arc wall 46 protrudes from a radially outer end
portion of the second wall 45 in the second rotational direction
D2. The second arc wall 46 has an arc shape whose center is the
second axis 22X. An outer circumferential surface of the second arc
wall 46 and the outer circumferential surface of the base portion
41 are flush with each other. The outer circumferential surface of
the second arc wall 46 and the outer circumferential surface of the
base portion 41 are rotatably supported by the inner
circumferential surface B12 (see FIG. 6) of the shaft 27B. That is,
the outer circumferential surface of the second arc wall 46 and the
outer circumferential surface of the base portion 41 are in contact
with the inner circumferential surface B12 of the shaft 27B.
[0082] The coupling 22 further includes a first tubular portion 22D
as illustrated in FIG. 8(a) and a second tubular portion 22E as
illustrated in FIG. 8(b). The first tubular portion 22D and the
second tubular portion 22E have a hollow cylindrical shape. An
outer diameter of the second tubular portion 22E is greater than an
outer diameter of the first tubular portion 22D. An inner diameter
of the second tubular portion 22E is greater than an inner diameter
of the first tubular portion 22D.
[0083] The coupling 22 further includes a partitioning wall 22F.
The partitioning wall 22F is positioned between the second tubular
portion 22E and the first tubular portion 22D. The partitioning
wall 22F partitions an inner space of the second tubular portion
22E from an inner space of the first tubular portion 22D. The first
tubular portion 22D and the partitioning wall 22F form the first
recessed portion 22A. The second tubular portion 22E and the
partitioning wall 22F form a second recessed portion 22J. The
second tubular portion 22E is fitted with the outer circumferential
surface B11 (see FIG. 6) of the shaft 27B and is rotatably
supported by the shaft 27B.
[0084] The coupling 22 includes a first protruding piece 22G and a
second protruding piece 22H. The first protruding piece 22G and the
second protruding piece 22H are positioned in the second recessed
portion 22J. The first protruding piece 22G and the second
protruding piece 22H protrude from the partitioning wall 22F. The
first protruding piece 22G has a first coupling surface FP1, a
third coupling surface FP3, and a fifth coupling surface FP5.
[0085] The first coupling surface FP1 is a surface for moving the
clutch 40 from the first position toward the second position in a
case where the clutch 40 rotates in the first rotational direction
D1. The first coupling surface FP1 is directed downstream in the
first rotational direction D1. The first coupling surface FP1 is
inclined relative to the rotational direction of the coupling 22.
Specifically, as illustrated in FIG. 8(d), the first coupling
surface FP1 is inclined so as to be away from the partitioning wall
22F as it goes in the first rotational direction D1.
[0086] The third coupling surface FP3 is a surface for moving the
clutch 40 from the second position toward the first position in a
case where the coupling 22 rotates in the second rotational
direction D2. The third coupling surface FP3 is directed downstream
in the second rotational direction D2. The third coupling surface
FP3 is inclined relative to the rotational direction of the
coupling 22. Specifically, the third coupling surface FP3 is
inclined so as to approach the partitioning wall 22F as it goes in
the second rotational direction D2. The third coupling surface FP3
is configured to contact an end portion of the second wall 45 of
the clutch 40.
[0087] The fifth coupling surface FP5 is a surface which contacts
the second wall 45 of the clutch 40 in the rotational direction in
a case where the coupling 22 rotates in the second rotational
direction D2. The fifth coupling surface FP5 is positioned farther
from the partitioning wall 22F than the third coupling surface FP3
is from the partitioning wall 22F. The fifth coupling surface FP5
crosses the rotational direction of the coupling 22. Preferably,
the fifth coupling surface FP5 is orthogonal to the rotational
direction of the coupling 22.
[0088] As illustrated in FIG. 8(c), the second protruding piece 22H
has a second coupling surface FP2, a fourth coupling surface FP4,
and a sixth coupling surface FP6. The second coupling surface FP2
has a shape the same as the shape of the first coupling surface
FP1. The fourth coupling surface FP4 has a shape the same as the
shape of the third coupling surface FP3. The sixth coupling surface
FP6 has a shape the same as the shape of the fifth coupling surface
FP5. The second coupling surface FP2 is positioned at the opposite
side to the first coupling surface FP1 in a state where the second
axis 22X is interposed between the first coupling surface FP1 and
the second coupling surface FP2.
[0089] The second coupling surface FP2 is a surface for moving the
clutch 40 from the first position toward the second position in a
case where the clutch 40 rotates in the first rotational direction
D1. The second coupling surface FP2 is directed downstream in the
first rotational direction D1. The second coupling surface FP2 is
inclined relative to the rotational direction of the coupling 22.
Specifically, as illustrated in FIG. 8(d), the second coupling
surface FP2 is inclined so as to be away from the partitioning wall
22F as it goes in the first rotational direction D1.
[0090] The fourth coupling surface FP4 is a surface for moving the
clutch 40 from the second position toward the first position in a
case where the coupling 22 rotates in the second rotational
direction D2. The fourth coupling surface FP4 is directed
downstream in the second rotational direction D2. The fourth
coupling surface FP4 is inclined relative to the rotational
direction of the coupling 22. Specifically, the fourth coupling
surface FP4 is inclined so as to approach the partitioning wall 22F
as it goes in the second rotational direction D2. The fourth
coupling surface FP4 is configured to contact an end portion of the
first wall 43 of the clutch 40.
[0091] The sixth coupling surface FP6 is a surface which contacts
the first wall 43 of the clutch 40 in the rotational direction in a
case where the coupling 22 rotates in the second rotational
direction D2. The sixth coupling surface FP6 is positioned farther
from the partitioning wall 22F than the fourth coupling surface FP4
is from the partitioning wall 22F. The sixth coupling surface FP6
crosses the rotational direction of the coupling 22. Preferably,
the sixth coupling surface FP6 is orthogonal to the rotational
direction of the coupling 22.
[0092] Prior to description as to functions of the coupling 22, the
clutch 40, and the shaft 27B with reference to FIGS. 9 and 10,
lengths of the first coupling surface FP1 and the like in the axial
direction will next be described. Note that, in FIGS. 9 and 10, the
structures of the coupling 22 and the like are simplified by
omitting or breaking away a portion thereof for better
understanding of the drawings.
[0093] As illustrated in FIG. 10(b), lengths of the first coupling
surface FP1 and the second coupling surface FP2 in the axial
direction are greater than a length of the second shaft surface FS2
in the axial direction, respectively. By this configuration, in a
case where the clutch 40 is positioned at the second position, each
tip end of the second protrusions P2 of the clutch 40 can be
positioned spaced away from each tip end of the first protrusions
P1 of the shaft 27B in the axial direction.
[0094] Further, lengths of the third coupling surface FP3 and the
fourth coupling surface FP4 in the axial direction are greater than
the length of the second shaft surface FS2 in the axial direction,
respectively. This configuration can increase amounts of meshing
engagement between the second protrusions P2 of the clutch 40 and
the first protrusions P1 of the shaft 27B in a case where the
clutch 40 is positioned at the first position.
[0095] Further, the lengths of the first coupling surface FP1 and
the second coupling surface FP2 in the axial direction are greater
than the lengths of the third coupling surface FP3 and the fourth
coupling surface FP4 in the axial direction, respectively.
[0096] Next, functions of the coupling 22, the clutch 40, and the
shaft 27B will be described. In the following description,
functions of the coupling 22, the clutch 40, and the shaft 27B in a
state where the developing cartridge 10 is attached to the drum
cartridge 5 will be described. That is, functions of the components
in a case where the coupling 22 rotates in the first rotational
direction D1 or the second rotational direction D2 in a state where
the developing roller 12 is pressed against the photosensitive drum
5B by the pressure member 5C will be described.
[0097] As illustrated in FIGS. 9(a) and 9(b), in a case where the
clutch 40 is positioned at the first position, the fifth coupling
surface FP5 and the sixth coupling surface FP6 of the coupling 22
engage with the fourth surface 45B of the second wall 45 and the
second surface 43B of the first wall 43 of the clutch 40 in the
rotational direction, respectively. Further, the first clutch
surfaces FC1 of the clutch 40 engage with the first shaft surfaces
FS1 of the shaft 27B in the rotational direction, respectively.
Hence, in this state, even if the coupling 22 is urged to rotate in
the second rotational direction D2, the coupling 22 does not rotate
in the second rotational direction D2 by the engagement between the
fifth coupling surface FP5 and the fourth surface 45B and the
engagement between the sixth coupling surface FP6 and the second
surface 43B. Accordingly, the reverse rotation of the developing
roller 12 can be suppressed.
[0098] Note that, there is known an image forming apparatus capable
of performing duplex printing. In this image forming apparatus, for
performing duplex printing, an image is formed on the front side of
a sheet at an image forming unit and then the front and back sides
of the sheet is reversed. Thereafter, the sheet is returned to a
position upstream of the image forming unit and then an image is
formed on the back side of the sheet. In such an image forming
apparatus, there is a case where the photosensitive drum is rotated
in a predetermined direction at a time of forming an image on a
sheet, whereas the photosensitive drum is rotated in the reverse
direction opposite to the predetermined direction at a time of
reversing the front and back sides of the sheet. In such a case,
the developing roller may rotate in the reverse direction following
the photosensitive drum rotating in the reversing direction. Even
in such a case, the reverse rotation of the developing roller can
be stopped by the structure according to the present embodiment.
Specifically, in the present embodiment, if the developing roller
12 rotates in the reverse direction, the coupling 22 in meshing
engagement with the developing gear 23 rotates in the second
rotational direction D2. However, this rotation of the coupling 22
can be stopped by the clutch 40 whose rotation is stopped by
engagement between the protrusions P1 and the protrusions P2.
Accordingly, the reverse rotation of the developing roller 12 can
be suppressed.
[0099] When the coupling 22 rotates in the first rotational
direction D1 by receiving driving force in the state illustrated in
FIGS. 9(a) and 9(b), the first coupling surface FP1 and the second
coupling surface FP2 of the coupling 22 push the third clutch
surface FC3 and the fourth clutch surface FC4 of the clutch 40 in
the first rotational direction D1, respectively. Hence, the clutch
40 rotates together with the coupling 22 in the first rotational
direction D1.
[0100] When the clutch 40 rotates in the first rotational direction
D1, each of the second clutch surfaces FC2 of the second
protrusions P2 contacts a corresponding one of the second shaft
surfaces FS2 of the first protrusions P1, so that the clutch 40 is
pressed toward the one side in the first direction by the second
shaft surfaces FS2 to thereby move from the first position to the
second position. By this, each of the second protrusions P2 is
moved away from a corresponding one of the first protrusions P1 in
the axial direction. That is, each of the second protrusions P2 is
disengaged from a corresponding one of the first protrusions P1.
Then, the first coupling surface FP1 and the second coupling
surface FP2 of the coupling 22 press the third clutch surface FC3
and the fourth clutch surface FC4 of the clutch 40 toward the
second position, respectively. By this, the clutch 40 is positioned
at the second position as illustrated in FIGS. 10(a) and 10(b). In
this state, the second protrusions P2 are positioned spaced away
from the first protrusions P1 in the axial direction and thus the
rotation of the clutch 40 is not stopped by the first protrusions
P1, so that the coupling 22 rotates together with the clutch 40.
Accordingly, driving force can be satisfactorily transmitted.
[0101] When the coupling 22 rotates in the second rotational
direction D2 due to reverse rotation of the photosensitive drum 5B
from the state illustrated in FIGS. 10(a) and 10(b), the third
coupling surface FP3 and the fourth coupling surface FP4 of the
coupling 22 contact the end portion 45C of the second wall 45 and
the end portion 43C of the first wall 43 of the clutch 40,
respectively. By this, the clutch 40 is pressed and moved toward
the first protrusions P1 by the third coupling surface FP3 and the
fourth coupling surface FP4. When the clutch 40 is disengaged from
the third coupling surface FP3 and the fourth coupling surface FP4,
each of the first clutch surfaces FC1 of the second protrusions P2
contacts a corresponding one of the first shaft surfaces FS1 of the
first protrusions P1 as illustrated in FIG. 9(b). Thus, the
rotation of the clutch 40 in the second rotational direction D2 is
stopped by the first shaft surfaces FS1.
[0102] Then, when the coupling 22 slightly rotates in the second
rotational direction D2, the fifth coupling surface FP5 and the
sixth coupling surface FP6 contact the second wall 45 and the first
wall 43 of the clutch 40, respectively. Hence, the rotation of the
coupling 22 in the second rotational direction D2 is stopped by the
walls 43 and 45 of the clutch 40 whose rotation has been stopped by
the first shaft surfaces FS1.
[0103] Note that, the above-described functions are similarly
exhibited in a state where the developing cartridge 10 is detached
from the drum cartridge 5.
[0104] The following effects can be obtained in the present
embodiment. In the above-described embodiment, the clutch 40
rotates together with the coupling 22 in a case where the coupling
22 rotates in the first rotational direction D1. Further, in a case
where the coupling 22 is caused to rotate in the second rotational
direction D2, the clutch 40 engages with the portion of the shaft
27B and the clutch 40 and the coupling 22 do not rotate.
Accordingly, the coupling 22 can be suppressed from rotating of in
a reverse rotation (the second rotational direction D2) opposite to
a predetermined rotational direction (the first rotational
direction D1).
[0105] Leakage of toner due to the reverse rotation of the
developing roller 12 can be suppressed since the coupling 22 can be
suppressed from rotating in the reverse rotational direction (the
second rotational direction D2) opposite to the predetermined
rotational direction (the first rotational direction D1).
[0106] Since each of the first clutch surfaces FC1 of the second
protrusions P2 contacts a corresponding one of the first shaft
surfaces FS1 of the first protrusions P1 and thus rotations of the
coupling 22 and the clutch 40 can be stopped, the rotation of the
coupling 22 can be stopped satisfactorily.
[0107] The clutch 40 can be moved away from the first protrusions
P1 in the axial direction since the lengths of the first coupling
surface FP1 and the second coupling surface FP2 in the axial
direction are greater than the length of the second shaft surface
FS2 in the axial direction, respectively. Hence, the second
protrusions P2 of the clutch 40 and the first protrusions P1 of the
shaft 27B can be prevented from interfering with each other in a
case where the coupling 22 rotates together with the clutch 40 in
the first rotational direction D1.
[0108] The first coupling surface FP1 and the second coupling
surface FP2 are positioned at positions interposing the second axis
22X between the first coupling surface FP1 and the second coupling
surface FP2. Therefore, the clutch 40 can be pressed toward the
second position in a well-balanced manner by the coupling surfaces
FP1 and FP2, so that the clutch 40 can be smoothly moved to the
second position. That is, according to the present embodiment, the
clutch 40 can be smoothly moved toward the second position by the
two coupling surfaces FP1 and FP2 positioned in a state where the
second axis 22X is interposed between the two coupling surfaces FP1
and FP2.
[0109] Further, in the present embodiment, also in a state where
the developing roller 12 is pressed against the photosensitive drum
5B by the pressure member 5C, the coupling 22 can be rotated in the
first rotational direction D1 but can be prevented from rotating in
the second rotational direction D2.
[0110] While the present embodiment of the present disclosure has
been described, the present disclosure is not limited to the
above-described embodiment. Various changes are conceivable without
departing from the spirit of the disclosure.
[0111] In the above-described embodiment, the shaft 27B includes
the plurality of first protrusions P1 and the clutch 40 includes
the plurality of second protrusions P2. However, the shaft 27B need
not necessarily include the plurality of first protrusions P1 and
the clutch 40 need not necessarily include the plurality of second
protrusions P2. For example, the shaft may include a single first
protrusion. Further, the clutch 40 may include a single second
protrusion. Furthermore, in the embodiment, the first protrusion P1
has the first shaft surface FS1 and the second shaft surface FS2.
However, the first shaft surface FS1 and the second shaft surface
FS2 need not necessarily be provided at a single protrusion. For
example, one protrusion may have the first shaft surface. Further,
another protrusion may have the second shaft surface. Similarly,
one protrusion may have the first clutch surface. Further, another
protrusion may have the second clutch surface.
[0112] In the above-described embodiment, both the second shaft
surface FS2 and the second clutch surface FC2 are inclined surfaces
inclined relative to the rotational direction. However, both the
second shaft surface FS2 and the second clutch surface FC2 need not
necessarily be inclined surfaces. For example, one of the second
shaft surface and the second clutch surface may be an inclined
surface.
[0113] In the above-described embodiment, the coupling 22 has two
surfaces (FP1 and FP2) for moving the clutch 40 toward the second
position. However, the number of surfaces for moving the clutch 40
toward the second position is not limited to two. The coupling 22
may have one surface or not less than three surfaces for moving the
clutch 40 toward the second position.
[0114] In the above-described embodiment, the first coupling
surface FP1 and the third clutch surface FC3 are inclined surfaces
inclined relative to the rotational direction. However, both the
first coupling surface FP1 and the third clutch surface FC3 need
not necessarily be inclined surfaces. For example, one of the first
coupling surface and the third clutch surface may be an inclined
surface. Similarly, one of the second coupling surface and the
fourth clutch surface may be an inclined surface.
[0115] In the above-described embodiment, the first bearing member
27 includes the shaft 27B. However, the first bearing member 27
need not necessarily include the shaft 27B. For example, the casing
11 may include the shaft 27B. In this case, the first bearing
member 27 may have a hole to allow the shaft 27B to extend
therethrough.
[0116] In the embodiment described above, the developing cartridge
10 is configured separately from the drum cartridge 5, but the
developing cartridge 10 and the drum cartridge 5 may be integrally
configured.
[0117] In the embodiment described above, a monochrome laser
printer is exemplified as the image forming apparatus, but the
image forming apparatus may be a color image forming apparatus.
Furthermore, the image forming apparatus may perform exposure using
LEDs. Moreover, the image forming apparatus may be a copier or
multifunction device, for example.
[0118] Further, implementation can be performed with any
combination of the components employed in the above-described
embodiment and modifications.
* * * * *